A typical backlight driving of a liquid crystal (LC) panel uses a light emitting diode (LED) as a backlight source. One system uses a plurality of LEDs connected in series to form a lightbar driven to light by a boost voltage circuit. The typical backlight driving has no electrical leakage protection, so if a user touches a television or other liquid crystal display device that are in an electrical leakage state, the user may get shocked and it is dangerous.